regarding Centerline Trace extension

[brynn]

Hi Friends,
I'm recently investigating the Centerline Trace extension:  https://github.com/Moini/inkscape-centerline-trace

Apparently it requires the AutoTrace program, to work:  https://sourceforge.net/projects/autotrace/

Unfortunately, I can't figure out how to install it.  The README file says that installation instructions can be found in the INSTALL file.  There is no INSTALL file.

http://autotrace.sourceforge.net/

I followed a link to its website (which contains at least one suspicious link - meaning that the site is not very well maintained) where I found installation instructions, which says that it can only be compiled.  If that's true, it put this extension out of reach for most Inkscape users.

Does anyone know if there's an easier way to install AutoTrace?

Thanks for any comments 

[Moini]

Follow the instructions on the correct page, please (my fork was just made for making changes, which have long been incorporated into the extension):
https://github.com/fablabnbg/inkscape-centerline-trace

(although, the instructions should be identical on the link you gave and the one I'm giving here, but the code is not. Use the official code of the extension, please)

[brynn]

Sorry for misunderstanding.  I was acting on the info on the wiki page, where in the Notes section, it says

".... Improved version available at https://github.com/Moini/inkscape-centerline-trace . Requires autotrace...."

Oh no, the instructions are not the same.  The instructions for the fablab version include instructions for 0.92.2 (which are very different, and MUCH easier than for 0.92.?)

Anyway, thanks for the info

[brynn]

Oh geez!  I've been trying to help someone with a really huge image.  When I tried to use the Centerline Trace extension, it didn't work, and I got this error message:

C:\Program Files\Inkscape 0.92.2\inkscape\lib\python2.7\site-packages/PIL/Image.py:2371: DecompressionBombWarning: Image size (97432974 pixels) exceeds limit of 89478485 pixels, could be decompression bomb DOS attack.
  DecompressionBombWarning)
Megapixel limit (2.0) exceeded. Scaling down by factor : 6.97971969351
Couldn't trace the path. Please make sure that the checkbox for tracing bright lines is set correctly and that your drawing has enough contrast.

The image dimensions are 14,946 x 6519.  So it really is a huge image.

But what's with the DecompressionBombWarning / decompression bomb DOS attack ?  How can a program which is not (as far as I know) connected to the internet create a denial of service attack.  Is there some other meaning for DOS attack?  It doesn't mean dos which I think is the language used in very early MS operating systems?  Or is there some variation of 'denial of service' that I haven't heard of?

Maybe I should log off the internet before I use it??

[Moini]

No, just scale the picture down. Wiki page updated for changes with ink/stitch (the new name of lexelby's Inkscape Embroidery) and removed link to my repo for centerline trace.

[brynn]

No, just scale the picture down.

The problem was that the smaller version of the image was not giving adequate trace results.  So I wanted to use the full size, to get the best trace result as possible.  (extremely large image with very small sections of intense detail)

It just seems odd to me that Inkscape is concerned with alerting users to some potential security issue -- I mean AT ALL, in the first place.  But also, afaiu, DOS attacks can only occur on the internet, while Inkscape is not a web application.  Why does Inkscape alert about this?  It seems so odd to me, that I'm thinking of asking on the User mailing list about it.

[brynn]

In the end, it probably wasn't an appropriate image for a centerline trace.

I thought centerline trace would give one path, which splits the difference between the inside edge and the outside edge -- the difference between the paths which the regular Trace Bitmap creates -- the line in the center of the inside and the outside.  But apparently it tries to find the centerlines of the image.

[Moini]

It wasn't Inkscape that complained, but PIL, which might be running on web servers, like inkscape.org. Please don't bother people on the mailing list with this. It's all correct.

Centerline trace works as is described here: https://github.com/fablabnbg/inkscape-centerline-trace . I don't understand what kind of result you are describing.